(1) Field of the Invention
The invention pertains to a constant pressure sanitary pump with sanitary check valves possessing metering capabilities. The novel sanitary pump and check valves are capable of rapid disassembly for cleaning and maintenance. The novel pump utilizes a drive shaft for operation of a double action piston head that is capable of reliable and high speed operation having components and check valves that may be removed from the pump and cleaned and quickly reassembled for sanitary hygienic filling operations as is required in the food handling and pharmaceutical processing arts.
The simplicity of the novel sanitary pump and sanitary check valves also provide for high speed pumping operations in pressure ranges of 400 pounds per square inch (p.s.i.) and greater and pumping cycles in the range of about 20 to 200 cycles per minute and preferably in a range of 60 to 160 cycles 20 per minute to provide virtually constant flow. The novel sanitary pump includes interchangeable check valves designed for high speed and reliable operation which can be rapidly removed and interchanged and are compatible with CIP (clean-in-place) cleaning as is required for sanitary pumps and metering operations in sanitary environments such as is found in the pharmaceutical and food processing industry with CIP (clean-in-place) cleaning.
The novel sanitary pump provides a double acting piston coupled to a drive shaft which may be interchanged for left hand or right hand drives or provides for driving from both sides by a drive shaft disposed through the pump housing. Adjustment of the stroke of the double acting piston may be provided in the drive shaft or the drive motor which can be of various types of mechanical drivers such as motors of various types, including electric motors, as well as pneumatic drive motors for the operation of the novel sanitary pump with metering capabilities.
(2) Description of the Related Art
The prior art includes a variety of pumps for transporting various types of fluid and semi-fluid products to a filling machine designed for dispensing food and dairy products in sanitary operations. In the prior art, the pump for transporting such fluid material to a separate metering and filling pump is generally referred to as a dosing or feed pump, which provides input feed to a metering and filling machine which in many cases employ a double action piston cylinder combination for alternately transporting the fluid product to a filler head under constant pressure.
The feed pump or dosing pump is generally of many different configurations and include screw conveyors, single acting piston cylinder pumps, pressurized vessels, and other devices for supplying fluid under pressure to a metering filling machine which then employs a double acting piston for metering and transferring the fluid to fill heads. The known prior art has not combined a feed pump and a double acting constant pressure metering machine into a single constant pressure pump with metering capabilities for application in the food processing industry for filling containers with various food products such as milk, yogurt, cream, cream cheese, and other viscous products so that the fill product is delivered from the metering filling machine by a constant pressure sanitary pump to the fill heads.
The prior art metering filling machines typically employ a double acting piston cylinder combination and a combination of valves and adjustment mechanisms for metering the amount of fluid to a fill head. Representative prior art of metering filling machines include Lamb et al. U.S. Pat. No. 1,932,976, Lamb U.S. Pat. No. 1,470,381, Buford et al. U.S. Pat. No. 3,447,281, Curtis et al. U.S. Pat. No. 1,777,293 and Johanssen U.S. Pat. No. 3,370,759. These metering filling devices utilize a double acting piston for providing constant pressure operation for use in the food processing industry, i.e. Lamb et al. U.S. Pat. No. 1,932,976 and Buford et al. U.S. Pat. No. 3,447,281.
The prior art metering filling machines are not pumps, but instead include a pressure differential activated piston cylinder combination having rods disposed axially through the ends of the cylinder wall for determining the position of the piston head and operating the valves for a substantially free floating piston head. Johanssen U.S. Pat. No. 3,370,759 employs a free floating piston head without rods or shafts extending through either end wall of the cylinder and provides a truly free floating piston head which like the other prior art metering filling machines are activated by fluid pressure differential acting upon either side of the piston head.
Unlike the prior art, the novel sanitary pump utilizes a positively controlled pump drive shaft and does not employ a free floating piston head or a piston with a head for operation in a free floating pressure differential environment. The invention in marked contrast to the prior art, provides a double acting piston head cylinder combination having at least one drive shaft connected to the piston head for positively controlling and driving the piston head in the cylinder. The novel sanitary pump further includes metering capabilities, like the prior art, but in contrast to the prior art, the metering capabilities of the sanitary pump of the invention are achieved by positively controlling the position of the piston head within the cylinder of the novel sanitary pump.
The prior art metering and filling machines, instead of utilizing a drive shaft, utilize piston rods or shafts that extend through the end walls of the cylinders to adjust the position of the piston head in the cylinder or to activate various valving mechanisms to open or close various types of ball valves, tapered valves, such as in Lamb et al. U.S. Pat. No. 1,470,381, or pneumatically controlled valves such as in Buford et al. U.S. Pat. No. 3,447,281 for admitting pressurized fluid into the pressure differential operated piston head. The prior art valves utilized in the prior art metering and filling machine are not check valves and do not provide for high cycle pumping operations. Prior art valves of various designs and configurations while suitable for the metering and filling of machines, the prior art are not suitable for the high pressure, rapid cycled pumps of the invention.
The prior art also includes various types of manifold and valve arrangements for the double acting metering piston head cylinder combinations. Examples of such manifolds are included in Lamb et al. U.S. Pat. No. 1,932,976 and Shultz et al. U.S. Pat. No. 5,992,696. These manifolds and valves do not include check valves and such valves do not provide stem guide means and seat guide means for preventing radial motion of the valve. Furthermore, the valves of the prior art do not include check valves that are opened and closed by the positive pumping action of a positively controlled pump drive shaft connected to the piston head which positively drives and controls the operation of the piston head in response to the drive motor. The prior art check valves are designed to operate by the indirect pressure from a feed pump or dose pump imparted upon a substantially free floating piston head in a metering and filling machine as opposed to the direct pumping action of a pump drive shaft.
The novel sanitary pump of the invention utilizes reliable high speed sanitary check valves designed to open, close and obviate the problems of wear and tear encountered in a high pressure operation of up to 400 pounds per square inch (p.s.i.) and greater and high speed operation of from about 60 to 160 cycles per minute and up to 200 or more cycles per minute. The novel sanitary pump and sanitary check valves are designed for reliability as well as being easily cleaned by CIP (clean-in-place) procedures as well as being easily taken apart for periodic cleaning operations. CIP operations in food and pharmaceutical operations presume cleaning without disassembly, although ease of disassembly provides advantages in replacing parts or rapidly removing and replacing components or parts in the event of contamination.
The prior art does not include a sanitary pump having detachably sealable ends having a positively controlled piston head controlled by a drive motor of an electrical, gasoline or pneumatic configuration which positively controls the position of the piston head. The prior art has not provided a double acting sanitary pump having a sanitary check valve capable of high speed dependable operations for high speed cycles from 60 to 160 and up to 200 cycles per minute or more depending on the positively controlled piston head. The prior art has also not provided a novel seal for providing a compression sealing of the piston control shaft in one or both ends of the novel detachable and easily cleanable sanitary pump and sanitary valves by CIP or rapid disassembly into their component parts.